| Westside Tile & Stone | Westside Tile & Stone | — | (831) 737 9656 | Other | Vallecito · Calaveras County | — | — |
| Whittle Construction Services | Thomas Allen Whittle | — | (209) 483 0303 | Other | Altaville · Calaveras County | — | — |
| Wiebe Electric | Mark Jason Wiebe | info@indiantypefoundry.com | (209) 736 9980 | Electricians | San Andreas · Calaveras County | — | — |
| Wildfire Safety Solutions INC | Laurence Anthony Doyle | info@wss-inc.com | (209) 662 1836 | GC, remodel, ADU | Avery · Calaveras County | — | — |
| William Deplitch General Contractor | William Deplitch General Contractor | — | (209) 795 2666 | GC, remodel, ADU | Arnold · Calaveras County | — | — |
| William R Anderson Construction | William Robert Anderson | — | (209) 481 5635 | GC, remodel, ADU | Valley Springs · Calaveras County | — | — |
| Willis Plumbing | Willis Plumbing | — | (209) 754 9638 | Other | Valley Springs · Calaveras County | — | — |
| Wilson Electrical And Data | Larry Wayne Wilson | — | (209) 772 9198 | Electricians | Valley Springs · Calaveras County | — | — |
| Winfield Grading | Winfield Grading | — | (209) 404 5722 | Other | Copperopolis · Calaveras County | — | — |
| Withers Mechanical | Withers Mechanical | — | (209) 470 2047 | HVAC | Valley Springs · Calaveras County | — | — |
| Woody's Painting | Woody's Painting | — | (559) 760 1217 | Windows, patio, painters | Valley Springs · Calaveras County | — | — |
| Wright's Hardwood Floors | Wright's Hardwood Floors | — | (408) 353 1988 | Other | Copperopolis · Calaveras County | — | — |
| Young Const Co | Joe Leroy Young | — | (209) 293 1111 | GC, remodel, ADU | Wilseyville · Calaveras County | — | — |
| Zac's Tree Service | Zachary Ryan Gifford | — | (209) 598 5157 | Other | Valley Springs · Calaveras County | — | — |
| Ziehlke Excavation | Ziehlke Excavation | — | (209) 743 8493 | Other | Murphys · Calaveras County | — | — |
| Zig - Zag Electric | Atanassov Todor | — | (650) 307 4085 | Electricians | Arnold · Calaveras County | — | — |
| Zimmerman's Construction | Theodore Wade Zimmerman | dave@zimmermansconstruction.com | (209) 743 2191 | GC, remodel, ADU | San Andreas · Calaveras County | — | — |
| Zimmerman's Outdoor Construction | Gerald Evan Zimmerman | — | (209) 559 2227 | GC, remodel, ADU | San Andreas · Calaveras County | — | — |